Textile apparatus



Oct. 4, 1955 c. J. FLECKENSTEIN TEXTILE APPARATUS Filed Aug. 20, 1952 INVENTOR.

CHARLES J.FL.ECKENSTEIN United States Patent O TEXTILE APPARATUS Charles J. Fleckenstein, Harrisonburg, Va., assignor to Celanese Corporation of America, New York, N. Y., a corporation of Delaware Application August 20, 1952, Serial No. 305,410

Claims. (Cl. 66--86) This invention relates to textile apparatus and relates more particularly to a warp let-off mechanism for use in textile apparatus wherein a warp of yarns is drawn off a warp beam.

In many types of textile apparatus, a warp of yarns is drawn from a warp beam preliminary to being subjected to one or more textile operations. For example, in a warp knitting machine a warp of yarns is drawn from a warp beam and is passed to a knitting station where it is converted into a knitted fabric. To obtain a satisfactory product, it is essential that the tension on the warp of yarns be maintained within relatively narrow limits. In textile apparatus, such as warp knitting mechines, wherein the feed of the warp of yarns to the point which the textile operation takes place must be varied periodically, the maintenance of a'uiiiform tension on the warp of yarns presents a diflicult problem.

U. S. Patent No. 2,486,525 to Fuhrer et al. discloses a warp let-off mechanism according to which motor means is connected to the warp beam and the speed at which said motor means is caused to rotate is varied so as to maintain the tension on the warp of yarns within narrow limits. The mechanism disclosed in the Fuhrer et al. patent for varying the speed of the motor means comprises a movable spring-loaded tension bar over which the warp of yarns is trained as it passes from the warp beam to the knitting station, a reactor arm movable by said tension bar and electronic means operated by the movement of said reactor arm for varying the speed of the motor means. Through the use of this apparatus, it is possible to maintain the tension on the warp of yarns within narrow limits for the production of a high quality product.

As the warp of yarns is drawn off the warp beam and the outside diameter of the winding of yarns on the warp beam decreases, the average rotational speed of the warp beam must be increased to maintain uniform the average rate of feed of the warp of yarns from the warp beam. In the Fuhrer et al. patent, the same control means is used both to vary the rotational speed of the warp beam periodically to maintain a substantially uniform tension on the warp of yarns despite periodic variations in the rate at which the warp of yarns is drawn from the warp beam and to vary the average rotational speed of the warp beam to maintain uniform the average rate of feed of the warp of yarns from the warp beam. The use of a single control means to perform both these functions imposes added burdens on said control means. It also means that said control means must be designed to operate to vary the average rotational speed of the motor means over a wide range from the time a full Warp beam is put into service until the time all of the yarns on said warp beam have been drawn off.

It is an important object of this invention to provide a warp let-off mechanism which will be free from the foregoing and other ditficulties and which will be especially simple in construction and efficient in operation.

A further object of this invention is to provide a Warp 2,719,419 Patented Oct. 4, 1955 let-oft mechanism for a textile apparatus in which a warp of yarns is drawn off a warp beam preliminary to being subjected to one or more textile operations and in which motor means are connected to the warp beam, according to which control means are provided for varying the rotational speed of the motor means to maintain the tension on the warp of yarns within narrow limits and according to which separate automatic control means are provided for varying the average rotational speed of the motor means.

Other objects of this invention, together with certain details of construction and combination of parts, will be apparent from the following detailed description and claims.

According to the present invention, there is provided a warp let-01f mechanism for a textile apparatus wherein a Warp of yarns is drawn from a warp beam and is subjected to one or more textile operations. The warp letotf mechanism comprises motor means operatively connected to the warp beam and control means for varying the rotational speed of the motor means to maintain the tension on the warp of yarns within narrow limits. In addition, separate automatic control means are provided for varying the average rotational speed of the motor means to compensate for changes in the outside diameter of the warp of yarns as the yarns are drawn oif the warp beam.

As the Warp of yarns'is drawn off the warp beam it is passed over a movable tension bar which may be springloaded in a manner well known in the art. Variations in the tension of the warp of yarns will cause the tension bar to move and this movement may be caused to actuate a control means for regulating the speed of the motor means so as to keep the tension on the warp of yarns within narrow limits. With the decrease in the outside diameter of the warp of yarns on the warp beam, as yarn is drawn off the said warp beam, the average rate at which said yarns are let olf said warp beam will gradually decrease thereby tending to raise the tension on the yarns. This increase in tension will move the tension bar to a new position causing the control means to increase the rotational speed of the motor means so as to maintain uniform the average rate at which the warp of yarns is let off the warp beam. The continued movement of the tension bar brought about by the change in the outside diameter of the warp of yarns on the warp beam closes a switch which actuates a separate control means to increase the average rotational speed of the motor means. For example, if the first mentioned control means functions by changing the current flowing through the armature of the motor means, the second control means may function by changing the current flowing through the field of the motor means, or vice versa. Through the operation of this second control means which regulates the average rotational speed of the motor means, the first control means will always be kept operating in the same portion of its range.

The warp let-off mechanism of this invention is especially adapted for use with textile apparatus wherein the tension on the warp of yarns tends to vary periodically at a rapid rate, as in the case in warp knitting machines, wherein the tension on the warp of yarns tends to go through an entire cycle at the rate of hundreds of times per minute. it may, however, also be used with other types of textile apparatus.

A preferred embodiment of this invention is shown in the accompanying drawing wherein Fig. 1 is an end elevational view of a portion of the warp let-off mechanism, and

Fig. 2 is an end elevational view of another portion of the Warp let-off mechanism and a schematic circuit diagram of the control means for varying the rotational speed of the motor means.

Referring now to the drawing, the reference numeral 11 designates a warp beam from which a warp of yarns 12 is drawn preliminary to being subjected to one or more textile operations. After leaving the warp beam 11, the warp of yarns 12 passes over a tubular tension bar 13 that is movably supported by arms 14 that are fixed to a shaft 15 which is journalled for rotation in bosses 16 in the frame 17 of the warp let-off mechanism. The arms 14 may be spring-loaded in a manner well known in the art; for example, as shown in the Fuhrer et al. patent above-mentioned. The warp beam 11 is operatively connected to a motor, shown diagrammatically and indicated generally by reference numeral 18, comprising an armature 19 and a field 2% to which current is supplied from terminals 21, by means of a worm 22. fixed to output shaft of the motor, meshed with a gear 23 that is fastened to a gear 24. An idler gear 25 which meshes with the gear 24 transmits the motion of the 1 gear 24 to a gear 26 fastened to the warp beam 11.

During the operation of the textile apparatus, any variations in the tension on the warp of yarns 12 will tend to move the tension bar 13 thereby operating a control means 27, for example, of the type shown in the Fuhrer et a1. patent, to increase or decrease the speed of the motor 18 by changing the current flowing through the armature 19 of said motor. The change in the speed of the motor 18 will cause a proportionate change in the speed of the warp beam 11 to increase or decrease the rate at which the warp of yarns 12 is drawn off said warp beam to hold the tension on said warp of yarns within narrow limits.

As yarn is drawn off the warp beam 11 and the outside diameter of the warp of yarns 12 on the warp beam 11 decreases, the linear speed at which the warp of yarns is let off said warp beam will decrease gradually. This will cause the average tension on the warp of yarns 12 to increase gradually and pull the tension bar 13 downward, thereby causing the control means to increase the speed of the motor 18 so as to maintain the average rate of feed of the warp of yarns 12 at a constant value. The downward movement of the tension bar 13 will cause the arms 14 and the shaft 15 to which they are fixed to rotate in a counterclockwise direction, when viewed as in Fig. l of the drawing. Fastened to the end of the shaft 15 by means of a set screw 23 is a contact arm 29 forming part of a switch 31. The counterclockwise rotation of the shaft 15 will bring the contact arm 29 into engagement with a contact 32 that is mounted on an insulating block 33 fastened to the machine frame 17. Closing of the contacts 29 and 32 will complete the circuit from terminals 34 through coil 35 of a relay 36 and cause contacts 37 and 58 of said relay to close. Upon the closing of the contacts 37 and 38, current will flow from ter minals 39 through a motor 41. The motor 41, when energized, will drive slider 42 of a rheostat 43 which is connected in series with the field 20 of the motor 18 in such a manner as to increase the speed of said motor for any given position of the tension bar 13 and control means 27. As a result of the increased speed of the motor 18 the tension on the warp of yarns 12 will de crease, permitting the tension bar 13 to move upward carrying the contacts 29 and 32 away from each other and stopping the motor 41. This cycle of operations will be repeated at intervals so as to raise the average speed of the motor 18 in proportion to the decrease in the outside diameter of the warp of yarns 12 on the warp beam 11. As a result, the control means 27 will be operating in substantially the same part of its range from the time a fresh warp beam is placed in the textile apparatus until the time when all the yarn on said warp beam has been drawn off. When a fresh warp beam is placed in the apparatus, the slider 42 may be returned manually to its original position. Alternatively, if desired, an additional set of contacts may be provided in connection with the shaft 15 to close when the average tension on the warp of yarns 12 drops below a given value to drive the motor 41 in the opposite direction to return the slider 42 to its original position.

In operation, the motor 18 acts both to assist in driving the warp beam 11 and to brake the said warp beam. Thus, when the motor 18 is rotating at a speed which will tend to cause the gear 26 to move at a faster rate than the warp beam 11, the force of the said motor will be added to the force exerted by the tension in the warp of yarns 11 tending to rotate the said warp beam so that the rotary speed of the warp beam will increase. On the other hand, when the motor 18 is rotating at a speed which will tend to cause the gear 26 to move at a slower rate than the warp beam 11, a braking action will be exerted on said warp beam because of the locking action on the drive through the worm 22 and gear 23, which eifectively prevents the transmission of any driving force from the gear to the worm.

It is to be understood that the foregoing detailed description is given merely by way of illustration and that many variations may be made therein without departing from the spirit of my invention.

Having described my invention, what I desire to secure by Letters Patent is:

1. In a warp let-off mechanism for textile apparatus in which a warp of yarns is drawn off a warp beam, the combination with said warp beam of motor means operatively connected to said warp beam, control means for varying the rotational speed of the motor means to maintain the tension on the warp of yarns within narrow limits, and separate automatic control means operative during the regular draw-off operation of said textile apparatus for varying the average rotational speed of the motor means, said separate automatic control means including a normally open switch adapted to be closed when the tension of the warp of yarns reaches a predetermined value.

2. In a warp let-off mechanism for textile apparatus in which a warp of yarns is drawn off a warp beam and in which the tension on the warp of yarns tends to vary periodically on a short term basis, the combination with said warp beam of motor means operatively connected to said warp beam, control means for varying the rotational speed of the motor means to maintain the tension on the warp of yarns within narrow limits, and separate automatic control means operative during the regular drawotf operation of said textile apparatus for varying the average rotational speed of the motor means to compensate for changes in the outside diameter of the warp of yarns as the yarns are drawn off the warp beam, said separate automatic control means including a normally open switch adapted to be closed when the tension of the warp of yarns reaches a predetermined value.

3. In a warp let-off mechanism for textile apparatus in which a warp of yarns is drawn off a warp beam and is passed over a movable tension bar, the combination with said warp beam of motor means operatively connected to said warp beam, control means actuated by the movement of the tension bar with changes in the tension of the warp of yarns for varying the rotational speed of the motor means to maintain the tension on the warp of yarns within narrow limits, and separate automatic control means operative during the regular draw-off operation of said textile apparatus and actuated by changes in the average position of the tension bar for varying the average rotational speed of the motor means, said separate automatic control means including a normally open switch, one element of which is operatively connected to said tension bar, adapted to be closed when the tension of the warp of yarns reaches a predetermined value.

4. In a warp let-off mechanism for textile apparatus in which a warp of yarns is drawn off a warp beam and is passed over a movable tension bar, the combination with said warp beam of motor means operatively connected to said warp beam, control means actuated by the movement of the tension bar with changes in the tension of the warp of yarns for varying the rotational speed of the motor means to maintain the tension on the warp of yarns within narrow limits, separate automatic control means operative during the regular draw-01f operation of said textile apparatus for varying the average rotational speed of the motor means, and a pair of contacts operatively connected to the tension bar and arranged to be closed when the tension bar moves outside a given range for actuating said separate automatic control means.

5. In a warp let-off mechanism for textile apparatus in which a warp of yarns is drawn off a warp beam, the combination with said warp beam of a motor operatively connected to said warp beam, control means for changing the current flowing through the armature of the motor for varying the rotational speed of the motor to maintain the tension on the warp of yarns within narrow limits, and separate automatic control means for changing the current flowing through the field of the motor for varying the average rotational speed of the motor.

6. In a warp let-ofi mechanism for textile apparatus in which a warp of yarns is drawn off a warp beam and is passed over a movable tension bar, the combination with said warp beam of a motor operatively connected to said warp beam, control means actuated by the movement of the tension bar with changes in the tension of the warp of yarns for changing the current flowing through the armature of the motor for varying the rotational speed of the motor to maintain the tension on the warp of yarns within narrow limits, and separate automatic control means actuated by changes in the average position of the tension bar for changing the current flowing through the field of the motor for varying the average rotational speed of the motor means.

7. In a warp let-01f mechanism for textile apparatus in which a warp of yarns is drawn ofi a warp beam, the combination with said warp beam of motor means operatively connected to said warp beam through a meshing worm and gear having the worm operatively connected to the motor means whereby no driving force can be transmitted from the warp beam to the motor means, control means for varying the rotational speed of the motor means to maintain the tension on the warp of yarns within narrow limits, and separate automatic control means operative during the regular draw-off operation of said textile apparatus for varying the average rotational speed of the motor means, said separate automatic control means including a normally open switch adapted to be closed when the tension of the warp of yarns reaches a predetermined value.

8. In a warp let-oflf mechanism for textile apparatus in which a warp of yarns is drawn ofi a warp beam and is passed over a movable tension bar, the combination with said warp beam of motor means operatively connected to said warp beam through a meshing worm and gear having the worm operatively connected to the motor means whereby no driving force can be transmitted from the warp beam to the motor means, control means actuated by the movement of the tension bar with changes in the tension of the warp of yarns for varying the rotational speed of the motor means to maintain the tension on the warp of yarns within narrow limits, and separate automatic control means operative during the regular draw-off operation of said textile apparatus and actuated by changes in the average position of the tension bar for varying the average rotational speed of the motor means, said separate automatic control means including a normally open switch, one element of which is operatively connected to said tension bar, adapted to be closed when the tension of the warp of yarns reaches a predetermined value.

9. In a warp let-off mechanism for textile apparatus in which a warp of yarns is drawn ed a warp beam, the combination with said warp beam of a motor operatively connected to said warp beam through a meshing worm and gear having the worm operatively connected to the motor whereby no driving force can be transmitted from the warp beam to the motor, control means for changing the current flowing through the armature of the motor for varying the rotational speed of the motor to maintain the tension on the warp of yarns within narrow limits, and separate automatic control means for changing the current flowing through the field of the motor for varying the average rotational speed of the motor.

10. In a warp let-off mechanism for textile apparatus in which a warp of yarns is drawn ofi a warp beam and is passed over a movable tension bar, the combination with said warp beam of a motor operatively connected to said warp beam through a meshing worm and gear having the worm operatively connected to the motor whereby no driving force can be transmitted from the warp beam to the motor, control means actuated by the movement of the tension bar with changes in the tension of the warp of yarns for changing the current flowing through the armature of the motor for varying the rotational speed of the motor to maintain the tension on the Warp of yarns Within narrow limits, and separate automatic control means actuated by changes in the average position of the tension bar for changing the current flowing through the field of the motor for varying the average rotational speed of the motor.

References Cited in the file of this patent UNITED STATES PATENTS 2,450,484 Palmer Oct. 5, 1948 2,486,525 Fuhrer Nov. 1, 1949 2,597,136 Snyder May 20, 1952 2,627,592 Hutton Feb. 3, 1953 

1. IN A WARP LET-OFF MECHANISM FOR TEXTILE APPARATUS IN WHICH A WARP OF YARNS IS DRAWN OFF A WARP BEAM, THE COMBINATION WITH SAID WARP BEAM OF MOTOR MEANS OPERATIVELY CONNECTED TO SAID WARP BEAM, CONTROL MEANS FOR VARYING THE ROTATIONAL SPEED OF THE MOTOR MEANS TO MAINTAIN THE TENSION ON THE WARP OF YARNS WITHIN NARROW LIMITS, AND SEPARATE AUTOMATIC CONTROL MEANS OPERATIVE DURING THE REGULAR DRAW-OFF OPERATION OF SAID TEXTILE APPARATUS FOR VARYING THE AVERAGE ROTATIONAL SPEED OF THE MOTOR MEANS, SAID SEPARATE AUTOMATIC CONTROL MEANS INCLUDING A NORMALLY OPEN SWITCH ADAPTED TO BE CLOSED WHEN THE TENSION OF THE WARP OF YARNS REACHES A PREDETERMINED VALUE. 